1. Insulin inhibits its own secretion from isolated, perifused human pancreatic islets
- Author
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E. Finke, B. J. Olack, P. E. Lacy, D. W. Scharp, C. J. Swanson, Rosa Giannarelli, M. Mclear, Piero Marchetti, and Renzo Navalesi
- Subjects
medicine.medical_specialty ,Time Factors ,Endocrinology, Diabetes and Metabolism ,medicine.medical_treatment ,Biology ,Feedback ,Islets of Langerhans ,chemistry.chemical_compound ,Endocrinology ,Internal medicine ,Insulin Secretion ,Internal Medicine ,medicine ,Humans ,Insulin ,Incubation ,Cells, Cultured ,Pancreatic hormone ,geography ,geography.geographical_feature_category ,C-Peptide ,Dose-Response Relationship, Drug ,C-peptide ,Pancreatic islets ,General Medicine ,Islet ,Perfusion ,Kinetics ,Glucose ,medicine.anatomical_structure ,L-Glucose ,chemistry ,Basal (medicine) - Abstract
It is still a controversial question whether insulin suppresses its own secretion. We prepared pure human islets from three pancreases by collagenase digestion and density gradient purification. Aliquots of 200 islet equivalents (IE, 150-μm sized-islets) were sequentially perifused at 37°C with 3.3 mmol/l glucose (3.3G, 40 min), 16.7 mmol/l glucose (16.7G, 30 min) and again 3.3G (30 min) after 24 h, 37°C culture in CMRL 1066 medium with or without the addition of either 200 or 400 μU/ml human insulin in the incubation medium (6 replicates each). Insulin secretion was assessed by C-peptide (Cp) measurement in the perufusate. Without added insulin (C) and with 200 (Ins200) or 400 (Ins400) μU/ml added insulin, basal Cp release was 0.12±0.03, 0.14±0.02 and 0.14±0.04 ng/ml, respectively. At 16.7G, the first-phase secretion peak (expressed as Cp value) was significantly lower with Ins200 (0.47±0.13 ng/ml,P
- Published
- 1995
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